The invention has an object of providing grease reduced in an amount of the flying grease and an amount of the outgas, and superior in low-temperature characteristic, an antifriction bearing using the grease, an antifriction bearing device, and an information recording/reproducing device. A grease includes a base oil, and a thickener, the base oil includes mineral oil and poly-α-olefin, the poly-α-olefin is higher in mass than the mineral oil, the poly-α-olefin includes poly-α-olefin higher in kinetic viscosity than the mineral oil, the kinetic viscosity of the base oil at 40° C. is in a range of 40 through 90 mm.sup.2/s, and worked penetration is in a range of 200 through 250. Further, an antifriction bearing, an antifriction bearing device, and an information recording/reproducing device use the grease.

There is provided a grease composition for improving the chemical stability of the grease composition and increasing the fatigue life of a member in which the grease composition is used. The problems can be solved by a grease composition including a poly-α-olefin; a urea-based thickener; molybdenum dithiophosphate; and barium sulfonate, wherein a difference between an SP value of the urea-based thickener and an SP value of the poly-α-olefin is 3.5 or less.

Provided are a lubricating oil composition which contains a base oil (A) containing an ester-based oil (Al), and a polymer (B) having a constituent unit (b) derived from an alkyl (meth)acrylate, wherein the content of the polymer (B) is 0.1 to 10% by mass based on the total amount of the lubricating oil composition, the lubricating oil composition has a viscosity index of 350 or more, the lubricating oil composition has a BF viscosity at −40° C. of 4000mPa.Math.s or less, and the lubricating oil composition is used for an impregnated bearing, and an impregnated bearing impregnated with the lubricating oil composition. The lubricating oil composition has excellent lubricity in use in a wide temperature environment from a low temperature region to a high temperature region, is capable of maintaining excellent infiltration property even in an environment in which a temperature change between a low temperature and a high temperature is severe, and is suitable for use in an impregnated bearing.

A deep groove ball bearing providing an inner ring, an outer ring and a plurality of balls being arranged between the inner ring and the outer ring. The inner ring and the outer ring each include a raceway for the plurality of balls. Each raceway encompasses the plurality of balls symmetrically. The deep groove ball bearing is lubricated by a lubricant being arranged on each axial side of the plurality of balls. The raceways are offset in the same axial direction from the axial center of the inner ring and the outer ring such that the raceways are offset to the axial side of the deep groove ball bearing where the shear rate acting on the lubricant is higher than on the other axial side of the deep groove ball bearing.

A rolling bearing makes use of a porous rolling element and a selected kind of lubricant to impregnate with; is usable in various conditions; does not discharge foreign objects; and features low dust generation and long life. The rolling bearing includes an outer ring 2; an inner ring 1; and a plurality of rolling elements 3 assembled between mutually opposed outer ring track surface 2a and inner ring track surface 1a. The plurality of rolling elements 3 is provided by a combination of a porous rolling element 3a impregnated with a lubricant and a non-porous rolling element 3b.

To provide a fluid dynamic bearing lubricating oil base oil which is within a suitable 40° C. and 100° C. kinematic viscosity range capable of achieving both energy saving and high bearing rigidity, and is excellent in viscosity index, heat resistance (evaporation resistance), and low temperature fluidity. Provided is a fluid dynamic bearing lubricating oil base oil containing an isophthalic acid diester compound represented by the following general formula (1)

##STR00001## wherein R1 and R2 are the same or different and each represent a linear alkyl group having 6 to 10 carbon atoms.

A tribological system, comprising a main body and a sandwich lubrication, in which the sandwich lubrication includes a binder-free solid lubricant layer comprising a solid lubricant, and a lubricant layer comprising a lubricant. The binder-free solid lubricant layer and the lubricant layer are present as separate layers on the main body and wherein the mass ratio of solid lubricant to lubricant is at most 0.05:1

A thrust ball bearing retainer a large size of bearings with the bearing raceways being modified using a surface enhancement process such as hard anodizing coating, which provides low friction coefficient and initial wear rate. The retainer material is selected to be molded, synthetic resin, self-lubricated material reinforced with carbon fiber, molybdenum disulfide, and PTPE. This lubrication system eliminates the thermal induced bearing torque effect due to viscosity. The retainer contains multiply segments with an inner race guided configuration, an alternative ball pocket cross section design and a ball pocket slotted configuration (1) to reduce the thermal induced effects due to coefficient of thermal expansion mismatch between the raceway and the retainer material (2) to enhance the producibility of the retainer due to out-of-round, out-of-flatness and torsional wrap, and (3) to reduce the manufacturing cost. The pocket design with an oval cross section instead of a circular cross section also reduces the localized thermal induced effect which would otherwise result in a pinching condition between the ball and the retainer. The alternative slotted retainer pocket design is used to increase the compliance between ball/pocket interfaces, which helps to reduce the dynamic induced effects. The ends of the retainer segments are designed to reduce the interactive transferring, circumferential force between two adjacent segments.

A lubricant for a rolling-element bearing includes a conventional lubricant as a base lubricant and at least one first additive, wherein the first additive includes muscovite, and the lubricant includes a proportion of muscovite that is between 3% and 5%. Also a method of lubricating a rolling-element bearing using the lubricant and a method of repairing a rolling-element bearing using the lubricant.

A cage (5) for separating rolling bodies (2) for a bearing (1), particularly for a timepiece bearing, the cage having first openings (50) for receiving rolling bodies and at least one first contact zone (56) intended to come into contact with a bearing ring and having at least one first hollow formation (52).